George Telfer joins forces with Three’s Company to bring us a short account of the life of Graham Chapman – perhaps the least well-known of the five main Monty Python actors, in spite of playing the lead in their two best-known feature films. He is often known as the Pythons’ “straight man”, but this show probes deeply beneath the surface, and is nothing short of a revelation.

We first meet an obviously ill Chapman late in his career, wheelchair-bound and on the telephone. Flashbacks follow in quick succession, beginning with war-time Britain, and we meet an array of characters – his father, a policeman, doctors, dons at Cambridge and some Thespian luvvies, including a less than completely sympathetic portrayal of fellow-Python John Cleese. Telfer is superbly versatile, and you really feel all these different characters are there before you – the northern father is particularly effective, as are, briefly, the dithering Dons during his entrance interview. Towards the end, about 10 different voices can be heard in quick-fire succession, and it is difficult to see how Telfer has time to distinguish between them.

There is a Shakespearian-style narrator, but the main character is of course Chapman himself, whom Telfer portrays with a good deal of sympathy yet never masking the man’s flaws. Chief among these is his alcoholism, which is so extreme that absolutely everything – acting and writing, friends and lovers – plays second fiddle to it. Other interesting points about his life come to the fore, such as his love of mountains and rugby, the fact he was gay before it was legal (the timing of his eventual coming-out making him something of an icon) and his fateful pipe-smoking. Chapman emerges as a somewhat hesitant and self-effacing figure, at one stage referring sarcastically to his ‘critically acclaimed wit’, who in spite of moments of selfishness courageously faces up to his various demons.

The acting, accents and comic timing are of a very high standard, and there are some lovely comic touches. Predictably enough, a number of these refer to the Pythons’ own material – the ‘disagree… I don’t agree’ interlude brings to mind their ‘Argument’ sketch, and Chapman senior has more than a touch of their much-loved Yorkshiremen sketch (‘when I were a lad…’). The ‘Parrot’ sketch and summarising Proust are name-checked, and the high-voiced girls pretending not to be girls will be familiar to many aficionados. There are also absurd, surreal Pythonesque touches: the drama/humour police who complain about acting techniques at the most inappropriate moments could have come from the pen of the great men themselves. In fact the policemen interrupt several sketches before the punchlines, a technique often used by Chapman’s Colonel figure – ‘stop it! This film’s got too silly! – breaking, in his words, every comic rule in the book.

What you might not expect from this show is seriousness. But we are reminded that the theatre is not always a time for jokes; and neither was Chapman’s life. There is a deep sadness to some incidents, movingly created by both Telfer and the writing. As a young man confused by his sexuality or a pitiful drunk on the point of tears, blaming his symptoms on everybody and everything bar himself, Telfer is convincing, all the more so because of the contrast with the rest of the acting. As an actor he dominates the stage, pacing restlessly here and there; even his one forgotten line was dealt with so seamlessly that it was barely noticed.

The writing, directing and acting combine to make an engaging and entertaining portrayal of Chapman. We catch an accurate glimpse of the past, whether war-time Britain, Cambridge in the early 60’s or, more prominently, Britain in the 70’s – partly through the references to the sketches, and partly through the name-checking of iconic figures such as Mohammed Ali, Paul McCartney, or Chapman’s close friend Keith Moon. Today’s audience might wonder at the squeamishness of the BBC over the ‘hobbies’ sketch; Chapman often sought to offend as many people as possible, and even his funeral was conducted in this spirit. I’m not sure if this performance quite does that, but it is wittily written and moving, and Telfer’s various characters are mesmerising.